Luis did 23 more sit-ups than Umaima in the evening. Luis did 73 sit-ups. How many sit-ups did Umaima do?
Answer: Luis did 73 sit-ups, and Umaima did 23 fewer than that, so find the difference. The difference is $73 - 23$ sit-ups. He did $73 - 23 = 50$ sit-ups.